For solidwork/photoshops and many other softwares, they come with a "history" or revision log. You could always easily go back to the previous step of components or check how it changed.
Is there such thing for Eagle? There are tutorials out there, but it could only visualise the change, using it with GIT + looking through the codes to get the changes or indicating version no. and last update date as a form of version control.
Is there a way to say, for each component, there is an activity log on it? (i.e. R20 changed from 100 ohms to 300 ohms etc......)